Extending the life of anaesthetic circuit tubing and rationalising our suction waste stream

Project completed as part of the 2023-4 Sheffield Teaching Hospitals Green Team Competition.

Team members

● Tim Orr, Consultant Anaesthetist, Sustainability Lead Anaesthesia and Operating Services

● Poppy Robinson, Senior Operating Department Practitioner, Obstetric and Gynaecology Theatres

Setting / patent group: Obstetric and Gynaecology Theatres

Issues

1) Plastic breathing tubing is routinely used to connect patients to anaesthetic machines for ventilation and oxygenation enabling surgery under general anaesthesia. It may also be used to deliver nitrous oxide analgesia in the operating theatre. Breathing tubing for anaesthetic machines is validated by the manufacturers for 7 days use. This is an arbitrary duration and lacks scientific basis. The product does not need to be sterile, is not intended to be single patient use and the bacterial/viral filter is trusted to prevent respiratory pathogens contaminating the circuit and causing transmission of hospital acquired respiratory infections

2) Suction waste in the operating theatre is collected in plastic bags which should not be disposed of in the offensive waste stream because they are liquid and risk leakage. In the past, gelling agent was used to solidify the waste. In 2020, the National Patient Safety Agency issued an alert, restricting the use of gelling agent to “exceptional use only via a specialist team”. This led to the indiscriminate removal across our trust and suction waste in our maternity unit is now disposed of by high temperature incineration as anatomical waste in a rigid single-use bin.

Intervention

1) Circuit tubing: To extend the lifespan of the tubing from one week to one month (a 75% reduction). We identified widespread confusion and variation in practice relating to changing different components of the circuit and a misunderstanding of the infection control implications. We estimated a worst case number of uses over a period of a month and trialled robustness. We gained directorate governance group and infection prevention and control approval to introduce the change at Jessops (three theatres) for a period of 3 months as a pilot. If successful we will then roll out across all our theatres.

2) Suction waste: We estimated current carbon footprint of disposing of our suction waste in the current stream and model the use of gelling agent and disposal in the offensive waste stream.

Outcomes

1) Circuit tubing: our modelled figures differed from procurement data, so we have estimated a range in potential annual savings from £6,416-£51,107. We would save between 3,302-7,887 kgCO2e, equivalent to driving between 9,752-23,293 miles in an average car. However, we should be working to a standard practice and if we were to move towards this, the higher figure would be representative. There was widespread acknowledgement that the proposed intervention would reduce plastic waste and save money. 9/13 (69%) thought it would save them time and effort. 7/13 (53%) thought the current policy, as they understood it, didn’t make sense, demonstrating approval for our proposed changes.

2) Suction waste: Converting to gelling and disposing our suction waste in the offensive wastestream across maternity theatres would result in £10,487 and 8,258 kgCO2e saved, equivalent to driving 24,388 miles driven. 10/13 (77%) thought gelling and disposal in a bag was the best solution to suction waste disposal in Jessops. 5/13 (38%) of respondents thought gelling waste instead of boxing it would reduce their workload, the remainder thought it would have a neutral effect. Nobody thought it would add to their workload.

Key learning point

Staff engagement has been key to this project. It has been quite easy to gain acceptance in principle and highlights the tendency to make changes that have a destructive effect on the environment and costs without considering the consequences and alternatives.